Art of assembling loud-speakers



Jqne 24, 1930. I. s. BOBROVSKY ART OF ASSEMBLING LOUD SPEAKERS Filed Feb. 20, 1928 3 IIIIW 360R '5 R'OVSKY Y.

' ly satisfactory, since Patented June 24, 1930 UNITED STATES PATENT OFFICE,

IGOR S. BOBRO'VSKY, OF ROCHESTER, NEW YORK, ASSIGNOB, BY MESNE. ASSIGNMENTS, TO UNITED BEPRODUCEBS CORPORATION, A. CORPORATION OF NEW JERSEY ART OF ASSEMBLING LOUD-SPEAKERS Application filed February 20, 1928. Serial No. 265,532.

This invention relates to a method and tool for assembling loud speaker diaphragms upon a face plate, and more particularly to a method and tool for assembling or mounting diaphragms of the type shown in my copending application entitled Diaphragm mounting for loud speakers, Serial Number 203,956, filed July 7th, 1927, upon a faceplate of the typetherein shown.

In assembling such a diaphragm upon a face plate in the past, it has been proposed to utilize adhesives or other fastening means such as holding rin s, clamps or the like, for maintaining the e ge of'the diaphragm in desired space relation with the face plate. These arrangements have not proved entirethe use of adhesives provides a rigid connection, which may be undesirable in case of warping or other de-. formations of the face plate during transportation or in use, and the use of clamping rings, screws, and the like, is subject to the same objection; and is also undesirable since the time required to assemble the diaphragm upon its'face plate is objectionable,-particularly when it is desired to carry on the assembly of such devices on aquantity production basis. The diaphragm mounting o the typeshown and described in my copending application above referred to, isdesigned to permit between the edge of the diaphragm and the face plate, which will permit the rim to creep upon the face. plate, thereby eliminating excessive tension upon the ed e of the diaphragm. It is somewhat di cult, assembly operation with such a mounting, if the assembling is done by hand, and particularly when the assembly is carried on a quantity production basis.

It is an object of this invention to provide a method and a tool .for facilitating and greatly speeding up the process of assembling and mounting of diaphragms of the type described.

It is a further object of this invention to provide a relatively inexpensive tool which may be utilized in mounting such diaphragms and by which the method, accord.-

a self adjusting connection in su dh a manner that the iaphragms may be quickly and easily mounted in the desired position. v

Still further objects and advantages of my invention, will be apparent from the specification.

to my invention, ma be carried out in The features of novelty which I believe i to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its fundamental principles and as to its particular applications, will best be understood by reference to the specification and accompanying drawing, in which:

Figure 1 is a sectional view of a face plate with a diaphragm mounted thereon;

FigureQ is a sectional view of a diaphragm before mounting;

Figure 3 is an edge View of a face plate, partly broken away;

Figure 4: is a sectional View of the tool according to my invention just prior to the bending operation; and

Figure 5 is a detailed sectional view, after completion of the bending operation. a

The diaphragms of the type to which my f invention has particular application, are

provided with a flexible edge which may be formed, for example, by gluing an annulus of soft and freely flexible and inelastic material, such as kid, to the periphery of the diaphragm. The face plate, upon which such diaphragms are to be mounted, is provided with an opening corresponding approximatel in size to the size of the diaphragm, w ich openin is provided with an outwardly projecting ange; though not necessarily, this flange is outwardly flared, and the annulus has a.- width somewhat greater than the maximum width of the flange, whereby the overlap portion preferably, al- 1 of the annulus may be bent inwardly around the flange, and secured in position by a ten-y.

sioned member, such as an elastic band,

string or wire.

I In attempting to mount if the mountingis to be carried on entirely by hand, it is diflicult to fold down the annulus and secure it in position by means 10 the diaphragm,

of the tensioned membersince it is impos sible to carry-on the folding at all points on the peripher of the flange; when it is atpositionin tempted to old the annulus at a plurality of oints in succession, it is found to be very di cult to bring each folded portion under the tensioned member without displacing a portion which has already been arran ed in roper position. In accordance wit invention, I proceed to carry on the folding o ration at all points around the periphery o the annulus simultaneously or substantially so, and after the entire annulus has been folded down simultaneously, I posithe annulus simu taneously or substantially so, I provide a tool comprisin 'two parts; one, a su port or base prefera ly mounted for rotatlon about its center and comprising an upper portion adapted to support the diaphragm, and a lower portion adapted to support the face plate in desired space relation therewith; that is to say, in a manner so that the base of the diaphragm lies substantially in the plane of the outerrim of the flange on the face plate, and so that the diaphragm is symmetrically positioned with respect to the opening in the face plate.

The other portion of the tool comprises a top, preferably in the form of an annular ring corresponding in size and shape to the diaphragm and having a downwardly projecting flan e or lip extending around the ring, and 0% somewhat less depth than the height of the flange of the face plate, whereby the top may be brought down upon the base or support when the face plate and diaphragm are in the desired position and the edge or downwardly depending lip carried by the ring will engage the rim at all oints around the periphery thereof, and bend or fold it downwardly over the flange on the face plate. The top is also arranged to carry on its outer cylindrical face an expanded tensioned member, such as a rubber band and the downwardly projecting lip is made shorter than the flange, whereby the tensioned member may be pressed downward off the cylindrical carrying face, and will contact and engage the bent portion of the rim, maintaining it in position.

The projecting edge of the leather rim may be grasped by the fingers or by any suitable device such as a air of pliers andpulled taut, the rotationa mounting of the base facilitating this adjusting process by permitting free rotation of the entire assembly.

In order to permit the tightenin process to be carried out in the manner a ove described and yet to leave a predetermined desired amount of slack in the rim, there may be provided on the support a projecting annular bead and a corresponding annular groove in'the top member. In pulling this rim taut, it is apparent that the rim will follow the curve of this bead and when the top is removed and the face plate with its attached diaphragm lifted from the base or support, the desired and predetermined amount of slack will be present in the rim.

Referring now more particularl to Figure 1, 1O designates generically a ace plate of any suitable material, such as metal or wood, having an opening therein defined by an outwardly projecting flange 11: in case the face plate is of metal, the flange 11 may be formed integral with the face plate by turning in a portion thereof, and preferably the flange 11 is slightly flared outwardly, so as to prevent accidental displacement.of the mount.

The diaphragm itself comprises a central portion 12, such as a cone, to which is secured a flexible annulus 13, such as soft kid. The outer portion of the annulus 13 is folded downwardly over the flange 11, and secured in position by means of a tensioned member or members, which may comprise a rubber band 14, supplemented if desired, by

one or more turns of string or wire 15, suitably secured; for permitting the driving of the diaphragm from the apex, there may be utilized a metal cap C attached thereto.

Referring now more particularly to Fig ure 2, I have shown the form of diaphragm before mounting, in which .it will be observed that the rim 13 is attached to the periphe of the diaphragm 12 and extends outward v therefrom.

Referring now more particularly toFigure 4, the assembling tool comprises a base or support 20, provided with a locatin cylindrical ring 24 of approximately the 'ameter of the opening of the face late 10 to permit of the face plate 10 belng placed thereon and supported in the proper position. The base 20 is preferably rotatably mounted upon a suitable bench or table 22 carrying a bearing, diagrammatically shown as 21, by means of which the support 20 may be rotated with respect to the bench 22. The inner portion 23 of the support 20 is provided of a size and shape arranged to engage the inside of the diaphragm 12 and support it concentrically with respect to the face plate 10, and preferably with the periphery of the diaphragm 12 in the mentary tension member, such as strin taneously.

,5, and at this plane of the edge of the flange 11. For

the purpose of permitting the folding or bending of the-rim to be carried on at all points -around,the ed e thereof simultaneously, the top comprises an annular ring 25, preferably having a conical inner face 26 arranged to engage the diaphragm 12; the annular ring 25 is provided with an outer cylindrical face 29 extendin downwardly below the bottom surface 2% of the annular ring 25, and having a diameter just sufiicient to permit the top .to be moved downwardly to the position shown in Figure 5 with the diaphragm in position. The lower edge or lip of the member 29 engages the outwardly extending annulus 13 and bends it downwardly over the edge of flange 11 all around the periphery thereof simul- After the top has been forced down, it takes the position shown in Figure point the tension member 14:, which has previously been stretched and laced upon the outside of the cylindrical ace 29, is pushed downwardly until it passes off the lower edge thereof, whereupon it contracts and engages the bent portion of the annulus 13 with sufiicient frictional contact to prevent the same from working out of the desired position when the top is removed. After the top is removed, the face late and diaphragm may then be removed rom the support, after which a supple- 15 may be passed over the bent portion 0 thd rim 13 and secured in position.

In case it is desired that the rim 13 be slack as shown, an annular bead 30 may be provided u on the upper portion 23 of the support an a corresponding annular groove 28 may be provided in the lower face of the annular ring 25 of the top. It will be noted that when the top is moved to full enga ement as shown in Figure 5, the conical ace 26 thereof engages the dia hragm holding it firmly in position, so t at the periphery of the annulus 13 may be rasped and pulled taut without danger of eforming or distorting the diaphragm 12, as would be likely tohappen if the diaphragm were not supported. It will be seen, also, that the engagement of groove 28 and bead 30 takes up a certain amount of material of the annulus 13, and that even though the annulus be. pulled taut, as above described, when the assembly is removed from the support, the desired amount of slack will exist in the Thu 13. It will be apparent" that the amount of slack may be increased troduced may by increasing the height and width of the head 30 and that the amount of slack in-'.'

be decreased bydecreasing the height and width of said bead, and that if it is desired to eliminate any slack in the complete assembly, the bead 30 and the groove 28 may be omitted.

For the purpose of facilitating the handling of the tool, the annular portion 25 may be provided with an arched handle 31 v ner' my invention as particularly applied to the assembly of conical diaphragms havin a flexible annulus or rim, it is apparent t at m invention may be applied to'the assemblmg of other types of diaphragms aswell;

and the saving of time in assembling the diaphragms according to my; invention, is so great as compared witht e prior methods involvingthe use of glue, holding rings, etc., that the number of'operators required for this phase of operations in the assembling of loud s eakers, is reduced to a fraction of those ormerly necessary.

While I have shown and described certain preferred forms of my invention, it will be apparent that modifications and changes may be'made without departing from the spirit and scope of my invention, as will be understood by those skilled in the art.

1. A tool for mounting a diaphragm'having a flexible ed'ge,upon a plate having an opening therein and having an outwardly extendlng projection adjacent said opening, againstwhich said edge is to be mounte said tool comprising a base for supporting said diaphragm and said plate in desired space relation, and a top arranged to engage said edge and bend it over said projection.

2. A. tool for mounting a diaphragm having a flexible edge, upon a plate having an openin therein and having an outwardly extending projection adjacent said opening, against which said edge is to be mounte said tool comprising a base for supporting said diaphragm and said plate in desired space relation, and a to arranged to engage said edge and bend it over said projection, said top being arranged to carry thereon an expanded tension member releasable to retain said edge in bent position.

3. A tool for mounting a diaphragm having a flexible edge, upon a plate having an openin extending against saidtool comprising a basefor supporting said diaphragm and said plate in desired space relation, and a top arranged to engage said edge and bend it over said projection, said base and said top being so shaped as to leave said edge slack between said dia-' phragm and. said plate after mounting.

4:. A tool for mounting a diaphragm having a flexible edge, upon a plate having an opening therein and having an outwardly extending projection adjacent said openi ng projection adjacent said opening,

therein. and having an outwardly roe and State of New York this 15th day against which said edge is to be mounted, said. tool comprising a base for support said diaphragm and said plate in desire space relation and a top arranged to engage said edge and bend it over said projection, said top having a face for carrying thereon an expanded tension member releasable to retain said ed e in bent position and the depth of said "Ewe being less than the depth ofoverl a V of said ed e upon said projection, whereby ateral disp acement of said tension member permits it to contract 4 upon the overlapped portion of said edge to maintain said edge yieldably in position upon said projection.

5. A tool for mounting a diaphragm having a flexible edge, upon a plate having an opening therein and having an outwardly extending projection adjacent said opening, against which said edge is to be mounted, said tool comprising a base for supportin said diaphragm and said plate in desire space relation and a top having an annular portion arranged toengage the inner portion of said rim, and a downwardly extending portion positioned around said annular portion and arranged to engage the outer portion of said rim and bend it over said projection, upon movement of said top into engagement with said base.

igned at Rochester in the county of Monof February A. D. 1928.

- IGOR S. BOBROVSKY. 

